1. Field of the Invention
The invention relates to a process for making a regenerated soil material, particularly to a process for making a regenerated soil material for the production of a structural unit, such as a wave-breaking block and the like. This invention also relates to the structural unit made from the regenerated soil material, and to a method for recycling the structural unit.
2. Description of the Related Art
Structural units, such as wave-breaking blocks and the like, are disposed at shores or river banks for flood protection. Conventional structural units are usually made by using a substantial amount of cement and sand as cementing material. However, the use of a substantial amount of cement and sand can arise in the following disadvantages:
1. A large amount of carbon dioxide is produced during the cement manufacture, which results in an environmental problem.
2. The sand used for the conventional structural units is usually obtained from a riverbed. Therefore, environmental damage is likely due to the over-exploitation of the riverbed for obtaining stones for making the sand.
3. The conventional structural unit is a concrete structure impermeable to water, and is usually different from the shore in color. Therefore, the view of the shore can be affected adversely.
4. The conventional structural unit made by blending sand with cement cannot be recycled or decomposed naturally. Therefore, when the conventional structural unit is discarded, it can cause permanent pollution to the environment.
Another conventional structural unit is made by using soil and cement as raw materials. The method for producing this conventional structural unit includes blending soil with cement into a mixture, and compacting the mixture by rolling to form the structural unit having a required density and strength. Although this conventional structural unit can be made without using sand, the production thereof is relatively complicated. Additionally, the compressive strength of the structural unit made from the soil and cement mixture is in a order below 10 MPa (mega-pascal), which is insufficient for practical use. Although the structural unit is made using soil as a primary material, the grains of the soil can bond to the cement after compacting, which in turn causes the structural unit to be impermeable to water.